Augmented Secretion of Atrial and Brain Natriuretic Peptides During Dynamic Exercise in Patients With Old Myocardial Infarction.

To assess the role of atrial and brain natriuretic peptides (ANP, BNP) in maintaining cardiac performance at rest and during exercise in patients with cardiac dysfunction, we measured plasma levels of ANP and BNP during 201Tl dynamic exercise testing in 32 patients with angiographically proven old myocardial infarction (OMI) and 35 normal control subjects (CS). Plasma levels of ANP and BNP at rest were significantly higher in patients with OMI than in CS (ANP, 42.6 +/- 19.3 vs 19.4 +/- 2.4 pg/ml, p < 0.01; BNP, 53.4 +/- 32.5 vs 2.8 +/- 0.8 pg/ml, p < 0.01, respectively). Correlations were found between plasma levels of these peptides and left ventricular ejection fraction (LVEF), cardiac index (CI), pulmonary capillary wedge pressure (PCWP) and left ventricular end-diastolic pressure (LVEDP) in patients with OMI. In addition, a strong positive correlation was found between plasma levels of these peptides and the severity score obtained from 201TI myocardial scintigraphy. During exercise, both ANP and BNP significantly increased in patients with OMI. However, in CS, although ANP increased, BNP remained unchanged. The changes in plasma levels of ANP or BNP from at rest to peak exercise correlated with LVEF, CI, PCWP, LVEDP and the severity score in patients with OMI. These findings indicate that ANP and BNP play an important role in maintaining cardiac performance at rest and during exercise in patients with cardiac dysfunction.